相关论文: Bounds on Contact Interactions from LEP1 Data and …
We discuss the possibility of explaining the excess in the cross section at high-Q^2 recently found at HERA in terms of four-fermion effective interactions. To avoid the constraints from low-energy data, we select three special cases in…
A search for physics beyond the Standard Model in neutral current deep inelastic scattering at high negative four-momentum transfer squared Q^2 is performed in e^{\pm}p collisions at HERA. The differential cross section ds/dQ^2, measured…
A search for physics beyond the Standard Model has been performed with high-Q^2 neutral current deep inelastic scattering events recorded with the ZEUS detector at HERA. Two data sets, e^+ p \to e^+ X and e^- p \to e^- X, with respective…
Data from HERA, LEP and the Tevatron, as well as from low energy experiments are used to constrain the scale of possible electron-quark contact interactions. Different models are considered, including the most general one, in which all new…
High-precision HERA data corresponding to a luminosity of around 1 fb$^{-1}$ have been used in the framework of $eeqq$ contact interactions (CI) to set limits on possible high-energy contributions beyond the Standard Model to electron-quark…
Deep-inelastic e^\pm p scattering at high squared momentum transfer Q^2 up to 30000 GeV^2 is used to search for eq contact interactions associated to scales far beyond the HERA centre of mass energy. The neutral current cross section…
We obtain bounds on the mass scales characterizing four-fermion contact interactions in charged current processes. The bounds arise from the Q^2 and x distributions in the processes e p -> \nu X measured by the two HERA experiments, H1 and…
We consider $e e q q$ contact interactions as a possible origin of an excess of events above Standard Model predictions in $e^+ p \to e^+ jet$ at high $Q^2$ observed by the H1 and ZEUS collaborations at HERA. The HERA data prefer chirality…
Forces beyond those of the standard model may manifest themselves at low energies as four-fermion contact interactions. If these new forces are independent of colour and flavour quantum numbers including baryon and lepton number, then all…
We reexamine the contact interaction hypothesis for excess high-$Q^2$ events seen at HERA in $e^+ p \to e^+ X$ scattering. We consider the most general structure of contact interactions insisting on $SU(3)_C\times SU(2)_L \times U(1)_Y$…
Effective $eeqq$ contact interactions can enhance event rates in $e^+p$ scattering at HERA at high $Q^2$. Present constraints from atomic parity violation measurements and from Drell Yan events at the Tevatron are discussed.
The high-precision HERA data allow searches for up to TeV scales "Beyond the Standard Model" contributions to electron-quark scattering. Combined H1 and ZEUS measurements of inclusive deep inelastic cross sections in neutral and charged…
We investigate to which extent an interpretation of the recently observed excess of events in the high $Q^2$ range at HERA in terms of single leptoquark production is compatible with bounds from other experiments.
The excess of high-Q2 events recently observed in deep-inelastic positron-proton scattering at HERA has refuelled speculations on physics beyond the standard model, in particular on low-mass leptoquark-type particles. We review the…
The reaction e+p --> e+X is studied with the H1 detector at Hera. The data cover momentum transfers Q^2 between 200 GeV^2 and 30,000 GeV^2 and correspond to an integrated luminosity of 35.6 pb^(-1). The differential cross section…
A previously proposed unified field theory of electro-strong interactions requires two scales of length within hadrons, $\sim10^{-15}m$ and $\sim10^{-18}m$ respectively, and the onset of new phenomena at the shorter scale. Studies at the…
The four fermion contact interactions, required to explain the anomalous HERA result, could come from the exchange of new heavy (probably composite) resonances. Depending on their charges and quantum numbers, one gets different scenarios…
In a search for signatures of physics processes beyond the Standard Model, various eeqq vector contact interaction hypotheses have been tested in the ZEUS experiment. No significant evidence of a contact interaction signal has been found.…
In a search for signatures of physics processes beyond the Standard Model, various eeqq vector contact-interaction hypotheses have been tested using the high-Q^2, deep inelastic neutral-current e^+p scattering data collected with the ZEUS…
We explore the capability of the Tevatron and LHC as well as other future hadron colliders to place limits on the possible existence of flavor-independent $q \bar q \gamma\gamma$ contact interactions which can lead to an excess of high…